https://doi.org/10.1351/goldbook.14057
Ratio of the rate of the photoreaction measured for a specified time interval (usually the initial conditions) to the rate of incident photons within a defined wavelength interval inside the irradiation window of the reactor.
Notes:
- A quantity called formal quantum efficiency (FQE) is sometimes used as synonymous for photonic efficiency and calculated from the known spectral distribution of the excitation source and the known absorption spectrum of the reaction system. It is calculated as the ratio between the rate of reaction and the incident photon flux.
- When monochromatic radiation is used, formal quantum efficiency is \(\xi\); otherwise formal quantum efficiency \(\neq \xi\).
- Mathematical definition: \[\xi = \frac{{\rm{d}}n/{\rm{d}}t}{\int_{\lambda_{1}}^{\lambda_{2}} q_{n,\rm{p},\lambda}^{0}{\rm{d}}\lambda}\] when using the incident spectral photon flux, chemical amount basis, \(q_{n,\rm{p},\lambda}^{0}\) with \(n\) (mol) the amount of substance produced or consumed, and \[\xi = \frac{{\rm{d}}N/{\rm{d}}t}{\int_{\lambda_{1}}^{\lambda_{2}} q_{\rm{p},\lambda}^{0} {\rm{d}}\lambda}\] when using the incident spectral photon flux, number basis, \(q_{\rm{p},\lambda}^{0}\) with \(N\) the number of entities produced or consumed. The superscript 0 (zero) emphasises the fact that the incident number of photons (prior to absorption) is used.